It is conventional to incorporate finely powdered grains or matting agents or particles into a layer of a photographic element to increase the surface roughness and achieve the following: (1) reduce blocking or reduce self-adhering of the material, (2) reduce friction and sticking of the material to itself and to manufacturing and processing devices, (3) improve the antistatic properties of the material, and (4) improve the vacuum adhesiveness of the material in contact exposure to prevent Newton's rings. The matting agents or matting particles are commonly very small particles of organic or inorganic polymeric materials such silicon dioxide, magnesium oxide, titanium dioxide, calcium carbonate, poly(methyl methacrylate), poly(vinyl toluene), poly(methyl methacrylate-co-methacrylic acid), and so on.
Particles used as matting agents are described in U.S. Pat. Nos. 4,855,219 and 4,022,622. Further, U.S. Pat. Nos. 4,396,706 and 5,057,407 provide matte particles and techniques in order to increase the adhesion of the particles to the photographic element during processing of the element. Further, U.S. Pat. No. 5,378,577 describes matte particles having a polymeric core material surrounded by a layer of colloidal inorganic particles. U.S. Pat. No. 5,198,408 describes the backing layer in a thermal dye transfer receiving element containing polymeric particles.
In a coating composition containing matte particles, a need exists for dispersants which will improve colloidal stability of the matte particles in the presence of ionic species, resulting in improved coating quality. The dispersant, ideally should prevent flocculation of the matte particles brought about by additives such as ionic antistatic agents.